/**
 * Exhaustiveness guard for if/else chains and switch/cases.
 *
 * Compile time: passing anything but `never` is a type error, so adding a new
 * union member without handling it fails to build. Runtime: an untrusted value
 * (e.g. an unknown message or error type from the wire) can still reach the
 * default branch, so throw an actionable error naming that value instead of
 * silently returning — callers previously received `undefined` and failed
 * later with no context.
 *
 * @param empty The value that should be unreachable
 */
export declare function assertNever(empty: never): never;